Scuticociliatosis caused by Uronema spp. is one of the most serious parasitic diseases of marine fish. The parasite has been reported to cause severe mortalities in cultured zobaidy, goat fish, sea horses etc. Antigenically similar and taxonomically related holotrichous ciliate, popularly known as marine “ich” Cryptocaryon irritans, is a serious parasite in all stages of sobaity, hamoor and zobaidy, causing almost a complete loss of cultured stock. Vibrio spp. have been associated with the opportunistic pathology of the weakened fish as it was seen in the case of zobaidy at the Kuwait Institute for Scientific Research (KISR) during 2005. (Note: An article by Azad et al., 2007).
Vaccines can provide a long term and effective remedy to these parasitic and bacterial infections in fish. However, the present invention takes care of difficulties and provides methods for the In vitro propagation and vaccine production of Vibrio-encapsulated Uronema spp. due to its antigenic similarity and taxonomic relatedness to protect against scuticociliatosis and marine ich. Also, the ability of the ciliate to feed on and concentrate Vibrio spp. in them will serve as a Vibrio and ciliate vaccine.
Fish aquaculture has been in vogue since times immemorial. Fish in aquaculture are susceptible to the threats of diseases. Fortunately, fish exhibit a very well developed immune system with the production of antibodies. Teleostean fishes are capable of eliciting a wide range of non-specific and specific immune responses that are comparable to the higher vertebrate immune systems (Clem, L. W. and Leslie, G. A., 1969. Journal of Experimental Medicine, 125:893-920; Hildemann, W. H. 1962. American Naturalist, 96:195-204; Ellis, A. E. 1988. Fish Vaccination (Ed. A. B. Ellis), Academic Press, London, P. 1-19).
Production of vaccine against parasites that are obligatory and cannot be cultured outside a fish host has been the major stumbling block in the production of commercial vaccines for marine fish. Holotrichous ciliates such as the ‘ichs’, Ichthyopthirius multifiliis (in freshwater fish), Cryptocaryon irritans (in marine fish) are the single most serious pathogens followed by opportunistic, yet increasingly threatening ‘velvet’ disease (Tetrahymena spp. in freshwater, Philasterides spp. and Uronema spp. in marine aquaculture systems).
Experimental immunization of catfish with Ichthyophthirius multifiliis has been reported (Becker et al., “Some Host Response of White Catfish to Ichthyophthirius multifiliis Fouquet”, Proc. 18th Ann. Conf. S.E. Assoc. Game and Fish Comm., 1964). More studies have shown that channel catfish injected intraperitoneally with vaccine prepared from the ground trophozoites, with and without Freund's adjuvant, survived challenge whereas control suffered 100% mortality after seven days (Areerat, S., “The Immune Response of Channel Catfish, Ictalurus punctatus (Rafinesque) to Ichthyophthirius multifiliis”, Masters Thesis, Auburn University, Auburn, Ala. (1974)). Clark et al. (1995) showed that the ‘I’antigen of the freshwater ‘ich’ produces strongly immunogenic response in naïve channel catfish.
The scuticociliates, notably Uronema spp. Miamiensis spp. and Philasterides spp. have been increasingly becoming serious threats to cultured marine fish. Uronema spp. caused high mortalities in cultured silver pomfret (Pampus argenteus) in Kuwait during 2005 (Azad et al., 2007). Other scuticociliates have also been reported to cause severe losses in cultured fish in different countries (Thompson and Moewus, 1964; Cheung et al., 1980; Yoshinaga and Nakazoe, 1993; Dykova and Figueras, 1994; Dragesco et al., 1995; Gill and Calinan, 1997; Munday et al., 1997; Iglesias et al., 2001). Uronema spp. has also been reported from farmed sea bass (Dicentrarchus labrax) in the Mediterranean (Dragesco et al., 1995), Japanese flounder, P. olivaceus (Yoshinaga and Nakazoe, 1993). The bluefin tuna (Thunnus maccoyii) infected with Uronema nigricans (Munday et al., 1997) and Uronema marinum (Jee et al., 2001) has been previously reported.
A prior art article by Azad, I. S., A. Al-Marzouk, C. M. James, S. Almatar, H. Al-Gharabally. 2007 is entitled “Scuticociliatosis-associated mortalities and histopathology of natural infection in cultured silver pomfret (Pampus argenteus Euphrasen) in Kuwait. Aquaculture 262:202-210.
A further article by Bassleer, G., 1983 reports on “Uronema marinum, a new and common parasite on tropical saltwater fishes. Freshwater Mar. Aquar. 6, 78-81.
In addition, an article by Cheung, P. J., Nigrelli, R. F., Ruggieri, G. D., 1980 reports on studies on the morphology of Uronema marinum Dujardin (Ciliatea: Uronematidae) with a description of the histopathology of the infection in marine fishes. J. Fish Dis. 3, 295-303.
In addition, an article by Jee, B. Y., Kim, Y. C., Park, M. S., 2001 reports on morphology and biology of parasites responsible for scuticociliatosis of cultured olive flounder Paralichthys olivaceus. Dis. Aquat. Org. 47, 49-55.
Finally, an article by Sterud, E., Hansen, M. K., Mo, T. A., 2000 reports on the systemic infection with Uronema-like ciliates in farmed turbot, Scophthalmus maximus (L.). J. Fish Dis. 23, 33-37.
In addition to the above, there are several patents of interests. To be more specific:
PCT/ES2007/070217 entitled “Philasteroides scuticociliate Vaccine For Marine Fish.” This patent discloses a method for preparing a vaccine against the principal pathogenous ciliates causing scuticociliatosis (genera. Philasterides/Miamiensis and Uronema) in farmed marine fish. The vaccine consists of trophozoites of the ciliates inactivated with formaldehyde and emulsified in an oil-based adjuvant. The vaccine administered to fish experimentally infected with the ciliates at concentrations from 104 to 108 cells per milliliter, inactivated with a concentration of formaldehyde less than 1% and emulsified in adjuvant at concentrations between 10 and 90%, led to a high degree of protection.
An earlier patent PCT/US2003/15408 relates to probiont and prebiont loaded zooplankton for improving health, growth and survival rates of larval fish, fish fry and crustaceans by feeding them probiont or prebiont-loaded zooplankton.
As reported therein production vaccine against parasites that are obligatory and cannot be cultured outside a fish host has been the major stumbling block in the production of commercial vaccines for marine fish. Holotrichous ciliates such as the “ich”, Ichthyopthirius multifilius (in fresh water fish), cryptocaryon irritans (in marine fish) are the single most serious pathogens followed by opportunistic, yet increasingly “velvet” disease (Tetrahymena spp. in fresh water, philasterides spp. and Uronema spp. in marine aquaculture systems).
The object of the present invention is to provide a treatment useful as a prophylactic for the management of fish diseases in mariculture and its applications in other aquatic animals. A particular object of the present invention is to provide a method as useful for producing and delivering a bath-cum-oral whole-cell inactivated Uronema spp. vaccine the development of an immune prophylactic for use in fish health management.
More particularly, an object of the present invention is to provide a method for the oral/bath delivery of Vibrios exemplified through Vibrio alginolyticus bioencapsulated in Uronema sp. during the production of the vaccine for fish health management.